This large ciliate is about 300 microns in length. It repeatedly twists its body to squeeze through a narrow space between aggregates. The aggregates gives us only a partial view of the ciliate’s body.

Commentary by Prof. Yuji Tsukii, Hosei UniversityFrom the shape of the cell and its dark cytoplasm, this organism looks like it might be Frontonia leucas. However, there are no trychocysts on the cell surface, and a large number of trycocysts is a key indicator to identify Frontonia leucas. This may be due to low magnification, or because this organism does not have trychocysts. If there are no or only a few trychocysts, this organism could possibly be Chilodontopsis. If the shape of the cytostome were shown clearly in this video, it would be easy to decide which organism it is.